1. Field of the Invention
The invention relates to the addition of a high temperature continuous strip anneal to routings for cube-on-edge oriented silicon steel and more particularly to such a high temperature continuous strip anneal performed after the decarburization step and before the final high temperature box anneal.
2. Description of the Prior Art
The present invention is directed to improvements in the manufacture of cube-on-edge oriented silicon steel. In cube-on-edge oriented silicon steel the body-centered cubes making up the grains or crystals are oriented in the cube-on-edge position, designated (110) [001] in accordance with Miller's indices.
Cube-on-edge oriented silicon steels are well known in the art and are commonly used in the manufacture of transformer cores and the like. In recent years prior art workers have devised various routings for the manufacture of cube-on-edge oriented silicon steel which have resulted in markedly improved magnetic characteristics. As a result, such oriented silicon steels are now considered to fall into two general categories. The first category is generally referred to as high permeability grain oriented silicon steel and is made by routings which consistently produce a product having a permeability at 796 A/m of greater than about 1850 and typically greater than about 1900. The second category is generally referred to as regular grain oriented silicon steel and is made by those routings normally producing a permeability of less than about 1850. U.S. Pat. Nos. 3,287,183; 3,636,579; 3,873,381 and 3,932,234 are typical of those which teach routings for high permeability grain oriented silicon steel. U.S. Pat. No. 3,764,406 is typical of those which set forth routings for regular grain oriented silicon steel.
The present invention is based upon the discovery that irrespective of the routing used, if the silicon steel is subjected to a high temperature strip anneal after decarburization and before the final box anneal, marked improvements will be obtained in both permeability and core loss. The teachings of the present invention are applicable to the manufacture of both high permeability grain oriented silicon steel and regular grain oriented silicon steel, the high temperature strip anneal being conducted within the parameters set forth hereinafter.